Apparatus for feeding printed sheets

ABSTRACT

Apparatus for feeding printed sheet material, such as signatures consisting of two or more pages (one or more sheets) or cards, from a large reserve stack to a small stack in a supply hopper of a collator. The apparatus includes a feeder frame which has a horizontal conveyor section that overlies the rear portion of the collator frame with its front end defining the rear of the hopper and a depending drive section that requires very little space to the rear of the collator. The apparatus has improved means for retaining the sheet material in the reserve stack and for forming and feeding the shingled stream.

United States Patent Swanson 1 1 Apr. 29, 1975 [54] APPARATUS FQR FEEDING PRINTED 3.176.981 4/1965 Vandcmzm .1 271/57 3.522.943 8/1971) Swanson 27l/D1G. 7 SHEETS 3.690650 9/1972 Mu1er. Jr. et ul. 271/D1G. 7 [75] In nt r: mit n up ll t 3705719 12/1972 P0111 ct 111. 271/D1G. 7

73 A551 nee: R. R. Don I] & Sons Com an 1 g 6 6y p y Primary Exuminer-Evon C. Blunk Ch1cdgo, ll1. Ass/slant Exanmzer-Bruce H. Stoner, Jr. [22] Flledi June 1 1973 Attorney, Agent, or FirmWegner Stellman, McCord, 121 App]. No.: 370,521 wood 157] ABSTRACT [52] Us. CL zg i /j Apparatus for feeding printed sheet material. such as 1511 1111. C1 B65h 3/04; B65h 29/18 222 2;: gfgi gglfi igxffil ig g ii i iggifi 2 1o. 7 g [58] Field ofSearch 71/3 7,D I t I 271/35 164 165 H4 99 701 203 DIG small stack 1n .1 supply hopper of a collator. The apptn A ratus includes a feeder frame which has a horizontal conveyor section that overlies the rear portion of the [56] R f C} d collator frame with its front end defining the rear of e erences I e the hopper and 21 depending drive section that requires UNITED STATES PATENTS very 1itt1e ,space to the rear of the collator. The appal.()87.121 2/1914 1c1fic1d ..L .1 271/35 X ratus has improved means for retaining the sheet ma- 13789138 9/1918 Comm 771/165 X terial in the reserve stack and for forming and feeding 2,192,265 3/1940 Ku11zlnder 1. 271/35 x the shingled stream 2378.306 6/1945 Leonhzlrt 1. 271/166 X 3.126.199 3/1964 Rosoff 271/35 X 27 Claims. 8 Drawing Figures PAYENTEBAPMQ Q SHEET 2 [IF 6 PATENTEDAFMQ i975 SHEEI u or 6 APPARATUS FOR FEEDING PRINTED SHEETS CROSS-REFERENCE TO RELATED APPLICATION This application includes general drawings and a general description of a collator of the inserter type which is especially adapted to accommodate the present apparatus. The inserter is described in detail and claimed in applicants copending application Ser. No. 370.522. filed June 15. 1973.

BACKGROUND OF THE INVENTION The present apparatus constitutes an improvement upon the structure ofSwanson US. Pat. No. 3.522.943. which is owned by applicant's assignee.

The apparatus of the above patent has effected a revolution in the handling of printed sheets such as signatures. whether they contain two pages or more. to maintain a supply of signatures in each box of a gathering machine. The apparatus of the patent is equally usable either with a flat gatherer of the type which feeds a patent binder or a side stitcher. or with the gatherers used in conjunction with saddle stitchers. which are commonly called inserters. However. the apparatus of the patent has certain limitations; and the present structure. while being much more compact than is that of the patent. provides superior handling and feeding of printed sheets to the collator. and greater versatility. than does the device of the patent.

SUMMARY OF THE INVENTION The present invention comprises a number of related improvements to the apparatus of US. Pat. No. 3.522.943 which cooperate to provide improved feeding of printed sheets from the large reserve stack into the collator hopper. In addition. certain ofthe improvements increase the versatility of the apparatus by permitting it to handle and feed signatures of more different dimensions and thicknesses than can be handled by the device of the patent. and which also permit it to handle cards that could not be fed by the device of the patent; and the present apparatus is extremely compact.

Improvements in the hopper structure for confining the large reserve stack of printed sheets function in cooperation with improvements in the means for feeding such sheets from the bottom of the reserve stack to permit more efficient handling of a variety of different types of material than is possible with the prior art apparatus. and in addition a more uniform shingled stream is formed for transfer to the collator supply box.

The conveyor drive control for the-shingled stream is improved to provide a steady flow of signatures to the collator hopper.

The term sheet material" is used herein as a generic term to include single printed sheets. also sometimes called two-page signatures. printed and folded sheets forming multi-print signatures. cards. or any other material that may need to be fed into a machine which is used to collate such material for binding.

THE DRAWINGS FIG. 1 is a schematic side elevational view of an inserter with the present sheet feeder mounted thereon;

FIG. 2 is a plan view. with parts in section and parts broken away, of the sheet feeder which also shows elements of the inserter sheet control;

FIG. 3 is a fragmentary section on a large scale. taken as indicated along the line 3-3 of FIG. 2. illustrating the structure of the laminar conveyor belts;

FIG. 4 is a fragmentary rear elevation view of sheet feeder;

FIG. 5 is a fragmentary sectional view of the sheet feeder taken substantially as indicated along the line 5-5 of FIG. 4'.

FIG. 6 is a fragmentary front elevational view of the sheet feeder:

FIG. 7 is a fragmentary sectional view taken substantially as indicated along the line 77 of FIG. 4 to illustrate the jogger and jogger drive. and

FIG. 8 is as view similar to FIG. I of a modified sheet feeder structure.

DETAILED DESCRIPTION OF THE INVENTION Referring to the drawings in detail. and referring first to FIG. 1. a collator has a series of printed sheet. or signature. supply and transfer boxes only one of which. indicated generally at 10. is illustrated in the drawings. The collator illustrated in the drawings is of the type which is commonly termed an inserter. and it has a conveyor chain 11 that extends along in front of the collator boxes 10 and is provided with spaced signature carriers 12 onto which opened signatures S are delivered from the boxes as the conveyor chain passes in front of them. In operation. each of the carriers 12 has an opened signature fed onto it from each of the boxes 10 so as to recive all the signatures required for a book. the book cover is fed onto the collated signatures at the last box. and the complete book passes to a saddle stitcher where it is bound by staples driven through the superimposed folded margins of the signatures which form the spine of the book.

The signature box 10 consists generally of a frame. indicated generally at I3. and surmounting frame 13 towards its front is a printed sheet hopper 14. Printed sheet delivery means. indicated generally at 15. includes a set of suction grippers 16. a pickup drum 17. a transfer drum 18 which is forward of the pickup drum. and a pair of opener rollers. indicated generally at 19. which are forward of the transfer drum l8 and flank the vertical median plane P of the carriers I2. Machine drive means. indicated generally at 20. includes a drive shaft 21 which extends through all the boxes 10 of the collator and is provided with drive sprockets 211:. A shaft 22 carriers a sprocket 220 which is driven from the sprocket 2111 by a chain 21b. A sheet transfer drive sprocket operates through a chain 23a to drive the sheet transfer means 15.

The printed sheet hopper I4 is adapted to contain a small stack ofprinted sheets or signatures S: and operatively associated with the hopper I4 is stack control means. indicated generally at 24. which includes stack height sensing means. indicated generally at 25. a stack lifter mechanism. indicated generally at 26. rotary corner brush means. indicated generally at 27. and a printed sheet front guide 28.

The inserter is particularly adapted for use with a signature feed apparatus. indicated generally at 30. by reason of the orientation of the signature hopper l4. and also by reason of the stock control means 24. Further. in order that the signature feed apparatus 30 may be mounted on the rear upper portion of the inserter 10. the machine frame 13 has parallel members with horizontal webs 29 on which the signature feed appara tus 30 rests so that it may be moved fore and after on the inserter.

The signature feed apparatus 30 consists generally of a frame. indicated generally at 31. which is generally of an inverted L shape and includes a horizontal conveyor section 32 and a vertical drive section 33 which depends from the rear of the conveyor frame section 32. The conveyor frame section 32 has horizontal supporting plates 34 at its two sides which rest upon the horizontal webs 29 of the machine frame 13. and the front end 35 of the conveyor frame section 32 defines the rear of the hopper 14. As illustrated in FIG. 1. the sig nature feed apparatus 30 is in its most rearward position with its front end 35 approximately inches from the front 14a (best seen in FIGS. 2 and 5) of the hopper 14 to accommodate a maximum 9 2 inch signature. By moving the feeder forward until the drive frame section 33 is substantially abutting the rear of the machine frame 13 the length of the hopper can be reduced to function properly with a minimum signature. or printed sheet. of 3 /8 inches which is the size of many cards used as book inserts in saddle stitched books.

Further to accommodate the feed apparatus 30. the shaft 22 is provided with a sprocket 36 which is mounted alongside the sprocket 23 and is of the same size; and a drive chain 37 makes a driving connection between the sprocket 36 and an input sprocket 38 which is keyed to an input shaft 39 journalled near the bottom of the feed apparatus drive frame section 33. the sprocket 38 drives a conveyor mechanism. indicated generally at 40. and a jogger mechanism. iridicated generally at 41.

Further cooperating with the feed apparatus 30 and with the stack height sensing means is a pulsating switch means. indicated generally at 42. which is driven from a sprocket 45 on the main machine drive shaft 21 through a chain 46 and a sprocket 47.

THE FEEDER STRUCTURE Referring now particularly to FIGS. 2 and 4 to 7. the frame 31 of the sheet feeder apparatus is seen to include conveyor section side plates 50 and 51. the front ends of which are connected by a spacer rod 52 and at the rear ends of which is a cross member 53 which is seen in FIG. 6 to be connected to the side frame members 50 and 51 by angle brackets 54 and 55. respectively. The member 34(F1G. 1) is seen in FIG. 6 to be welded into the side frame member 50. and a corresponding member 34a is welded into the side frame member 51. and said members 34 and 34:: are slotted brackets by means of which the feeder 30 is secured to the machine frame plate 39 by cap screws which extend through the slotted brackets to secure the feeder 30 in any desired adjusted position with reference to the hopper 14.

As seen in FIGS. 4 and 6, the cross plate 53 and a pair of angle brackets 56 and 57 provide mountings for the drive frame section 33 which includes side plates 58 and 59 the lower ends of which are connected by a spacer rod 60.

The conveyor means which is mounted in the conveyor frame section 32 is best seen in FIGS. 2. 4 and 5 to include a drive shaft 61 journaled in bearing blocks 62 and 63 which are adjustably mounted on the frame cross plate 53. Gussets 64 and 65 on the conveyor frame side plates and 51, respectively. are threaded to receive adjusting screws 64a and a for the bearing blocks 62 and 63. respectively. An end 6111 of the conveyor drive shaft 61 extends through the side plate 51 to receive a drive sprocket 61b. and on the shaft 61 are keyed fluted conveyor drive pulleys 66 and 67. Journalled on the front spacer rod 52 in alignment with the fluted pulleys 66 and 67 are smaller fluted idler pulleys 68 and 69: and over the aligned sets of conveyor pulleys are trained endless conveyor belts 70 and 71. Proper tensioning of the belts is achieved by longitudinal adjustment of the bearing blocks 62 and 63 on their respective mounting brackets 64 and 65.

The conveyor belts 70 and 71 are best seen in FIG. 3 to be of laminar construction including relatively wide commercial available outer belt members 72. known as Rufftop Neoprene belts. which are laminated to wire or nylon cord reinforced toothed timing belts 73 so as to have a positive drive between the fluted drive pulleys 66 and 67 and the conveyor belts 70 and 71.

Belt supporting and guiding means for the upper. or conveying runs of the belts 70 and 71 is provided by a conveyor floor indicated generally at 74. which includes a mounting plate 75 surmounting the forward portions of the conveyor frame side plates 50 and 51. a pair of mounting blocks such as the mounting block 76 seen in FIGSv 5 and 7. a rearward floor plate 77. and a forward floor plate 78. The rear end of the rearward floor plate 77 rests on the side plates 50 and 51 near the conveyor drive pulleys 66 and 67 and is inclined upwardly to a forward mounting on top of the mounting blocks 76'. and the forward floor plate 78 is inclined downwardly toward the front of the conveyor from an apex where it abuts the front of the floor plate 77 to a forward margin 7811 which is at the front of the mounting plate 75 just behind the idler pulleys 68 and 69. Thus. the belts are guided upwardly from the drive pulleys 66 and 67 to the front of the rear floor plate 77. and are then guided downwardly for a short distance to the front idler pulleys 68 and 69.

As best seen in FIGS. 2. 4 and 5, printed sheet guide means. indicated generally at 81. is operatively associated with the rear portion of the conveyor means to confine a large reserve stack of printed sheets which rests directly on the conveying runs of the belts 70 and 71 near the front of the rear conveyor floor plate 77. which thus provides a reserve stack holding area A (FlG. 7). The guide means 81 includes upright supporting posts 82 and 83. the lower end portions of which are secured to the conveyor frame side plates 50 and 51, respectively. A slotted cross plate 84 is secured between the upper end unions of the posts 82 and 83. and as best seen in FIG. 5 the cross member 84 is angularly adjustable with respect to the posts about pivot screws 85. with screws 86 being slidable in slots such as the slot 87 in the post 82. A pair of generally upright angle members 88 and 89 which confine the reserve stack at the rear are secured to the slotted cross member 84 by means of cap screws 88:: and 89a (FIG. 4) so that the distance between said angle members may be adjusted to accommodate printed sheets which are of varying lengths from head to foot. Likewise. the angles of the angle members 88 and 89 with respect to the rear conveyor floor plate 77 may be adjusted by tilting the slotted member 84 with respect to the supporting posts 82 and 83.

Also providing a part of the sheet guide means 81 is a pair of upright posts 90 and 91 which are mounted on the conveyor side plates 50 and 51. respectively. forward of the posts 82 and 82. Surmounting the posts 90 and 91 are hinges 92 and 93. respectively. and sheet engaging members in the form of plates 94 and 95 are connected by their upper ends to the hinges 92 and 93. respectively. The plates 94 and 95 may caused to project greater or lesser distances into the space between the posts 90 and 91 by means of transverse adjusting screws 96 and 97 which are threaded in holes in the posts 90 and 91, respectively. and have theirinner ends bearing upon the plates 94 and 95, respectively. The plates contact the lateral margins of printed sheets in the reserve stack to partially support those sheets and ease the load on the conveyors 70 and 71 is continuously moving the sheets off the bottom of the large reserve stack to form a shingled stream which is conveyed into the collator hopper 14.

Also mounted on the posts 90 and 91 is metering roller means, indicated generally at 98, which includes a 7 pair of longiudinally extending mounting brackets 100 and 101 which carry shaft brackets 100a and 101a that have vertical slots for adjustable mounting of a cross rod 102. The brackets may be mounted in any of several aligned pairs of holes in said arms; so that metering rolls 103 journalled on the cross rod may be adjusted fore-and-aft and vertically. The rollers 103 define the front margin of the reserve stack of printed sheets and confine said reserve stack at the front, as well as serving to control the depth of the shingled stream which is formed by the lowermost signatures in the reserve stack as they are moved forwardly away from the guiding anagle members 88 and 89.

As best seen in FIGS. 2 and 5, approximately at the forward extremities of the angle members 88 and 89. so as to be beneath the printed sheets in the large reserve stack. is a cross rod 104 which has its two ends mounted in the conveyor sides plates 50 and 51: and journalled on the cross rod 104 is a pair of rollers 105 which are best seen in FIG. 3 to be immediately adjacent the outer margins of the belts 70 and 71. The rol lers 105 have their outer surfaces formed of Rufftop Neoprene. and as best seen in FIG. 5 each ofthe rollers 105 includes an integrally connected drive pulley portion 106 which is engaged by the timer belt portion 73 of the belts 70 and 71. The uppermost portions of the rollers 105 project through openings in the rearward conveyor floor plate 77, so that the total surface area in contact with the lowermost sheet in the large reserve stack occupies a substantial proportion of the total head to foot length of the sheets although the belts 70 and 71, themselves, occupy only a minor fraction of that length.

The conveyor and conveyor frame structure are completed by a set of four depending bars 107 which is mounted at the front of the conveyor frame forward of the spacer rod 52 to define the rear of the hopper 14.

Referring now particularaly to FIGS. -4 and 5, the drive means for the conveyor 40 includes the input sprocket 38 on the shaft 39 which is journalled in the lower end portion of the frame drive section sides plates 58 and 59, and the input chain 37 which is trained around the input sprocket 38 and the sprocket 36 on the shaft 22 (FIG. 1). A tensioning sprocket 38a for the chain 37 is carried on a spring loader arm 600 which is mounted upon the lower cross rod 60 of the drive section frame 33. thus the input shaft 39 is constantly driven from the collator macahine drive shaft 21.

In order that the conveyor 40 may be driven intermittently. a solenoid clutch. indicated generally at 108 (FIG. 4). has an input portion 109 keyed on the shaft 39, and has an output disc 110 journalled on the shaft 39. Pinned to the solenoid clutch output disc 110 is a sprocket 111. and a drive chain 112 is trained over the sprocket 111 and the conveyor drive sprocket 6112. A chain tensioning sprocket 113 for the chain 112 is mounted on a pivotally adjustable arm 114.

As previously mentioned in the general description. the sheet feeding apparatus 30 also includes jogger means 41, and that means and the drive for it will now be described in detail with particular reference to FIGS. 4 and 7. Ajogger shaft 115 is journalled in bearings 116 and 117 which are mounted on the drive section side plates 58 and 59. and a jogger drive disc 118 which is eccentrically secured to the jogger shaft 115 is journalled in a bearing set 119 of a follower 120 the front end of which carries a pivot pin 120a for a yoke 12] of a jogger arm 122. Thus. rotation of the jogger shaft 115 causes the follower 120 to move in an orbital path. and produces short stroke motion of the jogger member 122.

The jogger mechanism also includes a push rod 123 which is connected to the upper end of the jogger arm 122, and which is slidable in a bushing 124 that is mounted beneath the rearward conveyor floor plate 77 so that the push rod is confined to linear movement. At the front of the jogger push rod 123. between the conveyor belts 70 and 71. is ajogger plate 125 which abuts the rear of the stack of sheets S in the hopper 14.

The jogger drive is through a counter shaft 127 which is journalled in bearing assemblies 127a and 1271) that are mounted upon the drive frame side plates 58 and 59, respectively. A sprocket 128 is keyed on the input shaft 39. a sprocket 129 is keyed on the counter shaft 127, and a drive chain 130 is trained around said two sprockets to drive the counter shaft 127. The counter shaft. in turn. carries a sprocket 131 with which a sprocket 132 on the jogger shaft 115 is aligned. and a drive chain 133 encircles the sprockets 131 and 132 to drive the eccentric shaft 115 from the counter shaft 127. As can be seen from the different sizes of the sprockets 128. 129, 131 and 132. the jogger shaft 115 is driven at a much higher rate of speed than the input shaft 39. The drive for the conveyor means 40. on the other hand. causes the conveyor drive shaft 61 to be driven considerably more slowly than is the input shaft 39.

The drive for the conveyor means 40 through the solenoid clutch 108 is controlled by the stack height sensing means 25 in the collator supply hopper 14, and by the pulsing switch means 42. The stack height sensing means 25 includes a plunger type limit switch 133 (FIG. 5) which is in the energizing circuit for the solenoid clutch 108. so that the clutch can only be energized to drive the conveyor means 40 when the switch 133 is closed. and that occurs only when a pile height sensing finger 134 senses that the top of the small stack of sheets in the hopper 14 is between predetermined limits. As seen in FIG. 1, a plunger type limit switch 135 of the pulsating switch means 42 is wired in series with the switch 133 in the energizing circuit for the solenoid clutch 108, so that the latter may be energized only when both switches are closed. A constantly pulsing current in the energizing circuit is provided by the drive means afforded by the sprocket 45. the drive chain 46. and the sprocket 47. Mounted on the shaft 470 which carries the sprocket 47 is a conjugate cam set 136, and a cam follower roller 137 which bears on the cam set 136 is carried on a pivoted arm 138. an actuating finger 139 of which bears upon the plunger of the switch 135. Tension in the chain 44 is maintained by an adjustable tensioning sprocket 44a which is slidably mounted on an arm 44h on the main machine frame 13.

As best seen in FIGS. 1 and 5. in order that an operator may have a reserve supply of sheets immediately adjacent the sheet guidemeans 81. a set of posts 140 which surmount the conveyor sections side plates 50 and 51 carry a sheet supporting tray 141 on which an extra stack of sheets is placed as seen in FIG. 1. The sheets in the extra stack as illustrated in FIG. 1 consists of multiple page signatures which are folded along their forward margins. which accounts for the elevated condition of the leading end of the extra stack.

The versatility ofthe present apparatus results principally from the various adjustments which may be made in order to obtain optimum handling of printed material having a large number of variations in addition to differences in sheet dimension. A thin signature-Le. one of two to four pages-obviously has totally different handling characteristics from a thick signature having. for example. 48 pages. Further. printed sheets handle totally differently depending on whether they are of 22 pound stock (typical telephone directly): or 60 pound stock (coated paper for coloring printed as used in periodicals of the highest quality); or something in between those two limits: or card stock which is 80 pounds. Finally. ofcourse. the finish ofthe sheetsi.e.. uncalendered. calendered. supercalendered or coatedaffects the handling.

The number of pages in a signature has an effect upon the amount of air in a stack of given height. and thus upon the load that can be placed in the hopper 14 and in the reserve stack. Likewise. sheets which have been stored for an extended period of time usually are more compressed. and thus heavier than fresh stock of the same paper and in signatures of the same number of pages.

The pile height sensing means associated with the hopper 14 may be raised and lowered to control the height of the stack in the hopper. Thinner signatures require a shallower stack.

Adjustment of the reserve stack supporting angle 88 and 89. in conjunction with adjustment of the reserve stack sheets engaging plates 94 and 95. also assists in proper feeding ofsheets from beneath the reserve stack and. in conjunction with adjustment of the metering rollers 103. controls shingle formation. Generally speaking. if the sheet material is densei.e.. signatures having few pages. or of heavy paper. greater rearward tilting of the supporting angles 88 and 89 takes some weight off the forward position of the reserve stack. while inward adjustment of the sheet engaging plates causes them to afford to greater support for the reserve stack. The greatest problem in the reserve stack is "rollups"i.e.. displacement of the sheets of a signature along the fold line. Rollup is avoided by reducing weight at the front of the reserve stack. as previously described.

Vertical adjustment of the metering rollers 103 to form a thinner shingle is generally desirable in the han dling of dense material.

Finally. uniformity of the shingled stream is more important in the handling of hard to handle" material; and a higher pulse rate on the pulse switching means 42 tends to provide greater stream uniformity by affording a quick. jerking motion of the conveyor belts.

ALTERNATIVE FORM OF SHEET FEEDING APPARATUS Referring now to FIG. 8, the alternative form of sheet feeding apparatus. indicated generally at 230, includes a frame structure. indicated generally at 231. which has a conveyor section 232 and a drive section 233. Both ends of the conveyor section overhand the drive section. so the frame is generally T-shaped. The feeder 230 is mounted upon a carriage 234 so that it may readily abe moved into position behind any box of a collator 10. Since the collator with which the sheet feeder 230 is illustrated is not materially different from the collator illustrated in FIG. I. like parts are given the same reference numerals which are not repeated at this point.

The sheet feeder 230 is illustrated with alternative arrangements for providing power to its input shaft 239 which is journalled in the drive section frame 233. In one form. an electric motor and gear box. indicated generally at 400. is mounted on a platform at the bot tom of the carriage 234. and a gear box output shaft 401 is provided with a sprocket 402 from which a chain 403 drives the input shaft 239 through an input sprocket 238. In the alternative arrangement. the drive is like that in the preferred form. with a drive chain 237 trained around a sprocket 36 on the shaft 22 and around the input sprocket 238. In the latter arrangement. of course. the drive chain 237 must have a link that may be readily opened to disconnect it from the sprockets 36 and 238.

The alternative form of sheet feeder also includes conveyor means. indicated generally at 240. and jogger means. indicated generally at 241.

The conveyor means 240 includes a drive shaft 242 which drives both a rearward conveyor. indicated generally at 240a. and a forward conveyor, indicated generally at 2401). Idler pulleys 244 at the rear of the rearward conveyor are aligned with one set of drive pulleys on the drive shaft 242 and carry rearward conveyor belts 245; while forward idler pulleys 246 are aligned with a second set of drive pulleys on the drive shaft 242 to drive forward conveyor belts 247.

Guide means 281 for a large reserve stack of sheets includes supporting posts 282 for a pair of sheet guiding angle members 289; and a pair of supporting posts 290 for hinged guide plates 294 which are adjustable by means of hand scres 296. Likewise. metering roller means. indicated generally at 298. includes upright supporting posts 299 which are mounted for longitudinally adjustment on the sides of the conveyor frame section 232. and metering rollers 303.

The foregoing detailed description is given for clearness of understanding only and no unnecessary limitations should be understood therefrom. as modifications will be obvious to those skilled in the art.

I claim:

1. Apparatus for feeding printed sheet material to a supply box of a collating machine which has a machine frame. a printed sheet supply hopper which holds a small vertical stack of printed sheets surmounting said frame toward the front thereof. said hopper having a front plate. drive means on the machine frame. and means mounted in the machine frame and driven by said drive means for withdrawing sheets by their leading ends seriatim from the bottom of the stack at a predetermined rate and delivering them to a gathering chain which travels along the front of the machine frame. said apparatus comprising. in combination:

a feeder frame which includes a horizontal conveyor section and a structurally integral drive section depending from said conveyor section. said feeder frame being adapted to be positioned with the forward part of the conveyor section overhanging the machine frame and the drive section immediately to the rear of the machine frame. the front of the conveyor section defining the rear of the sheet supply hopper. and the feeder frame being bodily movable fore and aft with respect to the machine frame to vary the length of said sheet supply hopper for handling sheets of different sizes;

conveyor means in the feeder frame conveyor section. said conveyor means including a transverse driven shaft journalled in the conveyor section above the drive section. a plurality of drive pulleys on said driven shaft. a plurality of idler pulleys journalled in the conveyor section aligned with the drive pulleys to provide pulley sets. and endless belt trained over each pulley set to form a top conveying run and a return run. and belt supporting and guiding means beneath the belt conveying runs. said belt conveying runs being inclined up- \vardly from the rear of the conveyor section to provide a reserve stack holding area. and the forward portions of said conveying runs being inclined downwardly from the rear for a short distance:

an input shaft journalled in the lower portion of the feeder frame drive section parallel to the driven shaft.

drive transmission means in the drive section operatively connecting said input shaft to said driven shaft;

means for driving said input shaft:

printed sheet guide and confining means operatively associated with the reserve stack holding area to hold a large reserve stack of printed sheets which rests directly on the belt conveying runs close to the front of the upwardly inclined portion of said runs. said guide and confining means including rear guides toward the rear of said holding'area and metering roller means at the front. said guide and confining means being adjustable laterally and longitudinally to confine printed sheets of different sizes.

means for adjusting the vertical position of the metering roller means to produce shingled streams of different depths.

means in the printed sheet supply hopper for sensing when the top of the small stack of printed sheets therein is between an upper level and a lower level;

and means controlled by said sensing means for causing driving of the conveyor driven shaft only when the height of said small stack is between said two predetermined levels. to draw printed sheets from beneath the reserve stack and feed them in a shingled stream to the supply hopper.

2. The apparatus of claim 1 in which the feeder frame is of an inverted L-shape. the driven shaft carrying the drive pulleys of the conveyor means is in the'angle of the L. the idler pulleys are at the front of the conveyor section. the tops of the drive pulleys and of the idler pulleys are substantially in the same horizontal plane. and the belt supporting and guiding means has a first portion that is inclined upwardly from the drive pulleys to an apex at an intermediate point close to the front of the reserve stack and a second portion that is inclined downwardly from said apex to the idler pulleys.

3. The apparatus of claim 1 in which the belts are spaced apart. there are openings in the belt supporting and guiding means alongside the belts and beneath the reserve stack. and driven rollers with concentric high friction surfaces project through said openings to a height substantially coplanar with the top of the belt conveying runs so as to cooperate with the belts to support and feed sheets from said reserve stack.

4. The apparatus of claim 3 in which the rollers have laterally extending integral drive drums in driven contact with the undersides of the conveyor belts.

5. The apparatus of claim 1 in which the printed sheet guide means includes a transverse pivotal mounting to vary the angle of the reserve stack relative to the conveyor belts.

6. The apparatus of claim l whieh includes a jogger shaft in the feeder frame drive section. an eccentric on said jogger shaft. a jogger at the front of the conveyor frame to jog the stack of printed sheets in the supply hopper. said jogger being operatively connected to the eccentric. and a driving connection between the input shaft and the jogger shaft.

7. The apparatus of claim 6 in which jogger drive transmission means between the input shaft and the jogger shaft drives the jogger shaft continuously. and a solenoid clutch between the input shaft and the driven conveyor shaft is engaged and disengaged in response to operation of the sensing means.

8. The apparatus of claim 1 in which the sensing means includes an actuator and an electrical limit switch. the means controlled by the sensing means includes a solenoid clutch for selectively transmitting driving force to the driven shaft. and a constantly pulsating electrical switch is wired in series with said electrical limit switchfthe solenoid clutch being engaged only when both of said switches are closed. the operating of said pulsating switching imparting a jerking movement to the conveyor.

9. The apparatus of claim 8 which includes eccentric cam means constantly driven by the drive means on the machine frame. and cam follower means for opening and,closing the pulsating electrical switch.

10. The apparatus of claim 1 in which the feeder frame is generally T-shaped. the conveyor means'includes a rear conveyor section to the rear of the driven shaft which inclines upwardly to the vicinity of said shaft and then downwardly. and a front conveyor section which extends from said shaft to the front of the feeder frame. and in which the printed sheet guide means confines the reserve stack on said rear conveyor section close behind the driven shaft.

11. The apparatus of claim 1 in which the printed sheet guide means includes inwardly extending. inclined. lateral sheet engaging members which contact the lateral margins of printed sheets in the reserve stack to partially support said stack and thereby relieve the weight on the sheets in the bottom portion of said reserve stack.

12. The apparatus of claim 11 in which means are provided to adjust the sheet engaging members laterally to vary the amount of support that they give to the reserve stack.

13. The apparatus of claim 12 in which the sheet engaging members are plates hinged at their upper ends; and the adjusting means comprises transverse screws engaging the lower portions of said plates.

14. Apparatus for feeding printed sheet material to a gathering machine which has a machine frame. a printed sheet supply hopper which holds a small vertical stack of printed sheets surmounting said frame toward the front thereof. said hopper havinig a front plate. drive means on the machine frame and means mounted in the machine frame and driven by said drive means for withdrawing sheets seriatim from the bottom of the stack at a predetermined rate and delivering them to a gathering chain which travels along the front of the machine frame. said apparatus comprising. in combination:

a feeder frame of inverted L-shape which includes a short horizontal conveyor section and a structurally integral drive section which is short from front to rear depending from the rear of said conveyor section. said frame being adapted to be.positioned with the conveyor section surmounting the machine frame and the drive section immediately to the rear of the machine frame;

upright members on the front of the conveyor section which provide rear confining means for the sheet supply hopper and the feeder frame being bodily movable fore and aft on the machine frame to vary the length of said hopper for handling sheets of different sizes;

conveyor means in the feed frame conveyor section. said conveyor means including a transverse driven shaft journalled at the rear of said conveyor section and at the top of the drive section. a plurality of drive pulleys on said driven shaft. a plurality of idler pulleys journalled at the front of the conveyor section aligned with the drive pulleys to provide pulley sets. an endless belt trained over each pulley set to form a top conveying run and a return run. and belt supporting and guiding means beneath the belt conveying runs. said belt conveying runs being inclined upwardly from the rear of the conveyor section to provide a reserve stacking holding area. and the forward portions of said conveying runs being inclined downwardly from the rear for a short distance:

an input shaft journalled in the lower portion of the feeder frame drive section parallel to and substantially in the same vertical plane as the driven shaft.

drive transmission means operatively connecting said input shaft to said driven shaft.

means for driving said input shaft:

adjustable printed sheet guide and confining means above the reserve stack holding area to hold a large reserve stack of printed sheets rests directly on the belt conveying runs close to the front of the upwardly inclined portion of said runs. said guide and confining means including rear guides toward the rear of said holding area and metering roller means at the front. said guide and confining means being adjustable laterally and longitudinally to confine printed sheets of different sizes;

means for adjusting the vertical position ofthe metering roller means to produce shingled streams of different depths: means in the printed sheet supply hopper for sensing when the top of the small stack of printed sheets therein is between an upper level and a lower level:

means controlled by said sensing means for causing driving of the conveyor driven shaft only when the height of said small stack is between said two predetermined levels. to draw printed sheets from be neath the reserve stack and feed them in a shingled stream to the supply hopper.

15. The apparatus of claim 14 in which the tops of the drive pulleys and of the idler pulleys are substantially in the same horizontal plane. and the belt supporting and guiding means has a first portion that is inclined upwardly from the drive pulleys to an apex at an intermediate point close to the front of the reserve stack and a second portion that is inclined downwardly from said apex to the idler pulleys.

16. The apparatus ofclaim 15 in which the axis ofthe metering roller means in a vertical plane close behind the apex of the belt supporting and guiding means.

17. The apparatus of claim 16 in which the metering roller means is mounted for linear adjustment toward and away from the guide means.

18. The apparatus of claim 17 in which the metering roller means is mounted for vertical adjustment to vary the depth of the shingle.

19. The apparatus of claim 14 in whch the printed sheet guide means includes inwardly extending lateral sheet engaging members which contact the lateral margins of printed sheets in the reserve stack to partially support said stack and thereby relieve the weight on the sheets in the bottom portion of said reserve stack.

20. The apparatus of claim 19 in which means are provided to adjust the sheet engaging members laterally to vary the amount ofsupport that they give to the reserve stack.

21. The apparatus of claim 14 in which the printed sheet guide means includes a transverse pivotal mounting to vary the angle of the reserve stack relative to the conveyor belts.

22. The apparatus of claim 14 which includes a jogger shaft in the feeder frame drive section. an eccentric on said jogger shaft. a jogger at the front of the conveyor frame to jog the stack of printed sheets in the supply hopper. said jogger being operatively connected to the eccentric, and a driving conection between the input shaft and the jogger shaft.

23. The apparatus of claim 22 in which jogger drive transmission means between the input shaft and the jogger shaft drives the jogger shaft continuously. and a solenoid clutch between the input shaft and the driven conveyor shaft is engaged and disengaged in response to operation of the sensing means.

24. The apparatus of claim 14 in which the belts are spaced apart. there are openings in the belt supporting and guiding means alongside the belts and beneath the reserve stack. and driven rollers with concentric high friction surfaces project through said openings to a height substantially coplanar with the top of the belt conveying runs so as to cooperate with the belts to support and feed sheets from said reserve stack.

25. The apparatus of claim 24 in which the belts and rollers are in contact with substantially more than onehalf the head to foot length of the sheets in the reserve stack.

26. Apparatus for feeding printed sheet material to a supply box of a collating machine which has a machine frame. a printed sheet supply hopper which holds a small vertical stack of printed sheets surmounting said frame toward the front thereof. said hopper having a front plate. drive means on the machine frame. and means mounted in the machine frame and driven by said drive means for withdrawing sheets by their leading ends seriatim from the bottom of the stack at a predetermined rate and delivering them to a gathering chain which travels along the front of the machine frame. said apparatus comprising. in combination.

a feeder frame which includes a horizontal conveyor section and a drive section depending from said conveyor section. said feeder frame being adapted to be positioned with the forward part of the conveyor section overlying the machine frame and the drive section immediately to the rear of the machine frame. the front of the conveyor section defining the rear of the sheet supply hopper. and the feeder frame being bodily movable fore and aft with respect to the machine frame to vary the length of said sheet supply hopper for handling sheets of different sizes;

conveyor means in the feeder frame conveyor section. said conveyor means including a transverse driven shaft journalled in the conveyor section above the drive section. a plurality of laterally spaced drive pulleys on said driven shaft. a plurality of idler pulleys journalled in the conveyor section aligned with the drive pulleys to provide pulley sets, an endless belt trained over each pulley set to form a top conveying run and a return run having spaced apart belts. and belt supporting and guiding means beneath and conveying runs. there being openings in the belt supporting and guiding means alongside the belts:

driven rollers with concentric high friction surfaces which project through said openings to a height substantially coplanar with the top of the belt conveying runs;

an input shaft journalled in the lower portion of the feeder frame drive section parallel to the driven shaft:

drive transmission means in the drive section operatively connecting said input shaft to said driven shaft:

means for driving said input shaft to drive the endless belts and the rollers:

printed sheet guide means operatively associated with the rear portion of the conveyor means to confine a large reserve stack of printed sheets which rests directly on the belt conveying runs and the driven rollers. said guide means being adjustable to confine printed sheets of different sizes:

means in the printed sheet supply hopper for sensing when the top of the small stack of printed sheets therein is between an upper level and a lower level.

means controlled by said sensing means for causing driving of the conveyor driven shaft only when the height of said small stack is between said two predetermined levels. to draw sheets from beneath the reserve stack and feed them in a shingled stream to the supply hopper:

and adjustably mounted metering roller means for controlling the depth of said shingled stream as it moves from under th reserve stack.

27. The apparatus of claim 26 in which the rollers have laterally extending integral drive drums in driven contact with the undersides of the top conveying runs 

1. Apparatus for feeding printed sheet material to a supply box of a collating machine which has a machine frame, a printed sheet supply hopper which holds a small vertical stack of printed sheets surmounting said frame toward the front thereof, said hopper having a front plate, drive means on the machine frame, and means mounted in the machine frame and driven by said drive means for withdrawing sheets by their leading ends seriatim from the bottom of the stack at a predetermined rate and delivering them to a gathering chain which travels along the front of the machine frame, said apparatus comprising, in combination: a feeder frame which includes horizontal conveyor section and a structurally integral drive section depending from said conveyor section, said feeder frame being adapted to be positioned with the forward part of the conveyor section overhanging the machine frame and the drive section immediately to the rear of the machine frame, the front of the conveyor section defining the rear of the sheet supply hopper, and the feeder frame being bodily movable fore and aft with respect to the machine frame to vary the length of said sheet supply hopper for handling sheets of different sizes; conveyor means in the feeder frame conveyor section, said conveyor means including a transverse driven shaft journalled in the conveyor section above the drive section, a plurality of drive pulleys on said driven shaft, a plurality of idler pulleys journalled in the conveyor section aligned with the drive pulleys to provide pulley sets, and endless belt trained over each pulley set to form a top conveying run and a return run, and belt supporting and guiding means beneath the belt conveying runs, said belt conveying runs being inclined upwardly from the rear of the conveyor section to provide a reserve stack holding area, and the forward portions of said conveying runs being inclined downwardly from the rear for a short distance; an input shaft journalled in the lower portion of the feeder frame drive section parallel to the driven shaft; drive transmission means in the drive section operatively connecting said input shaft to said driven shaft; means for driving said input shaft; printed sheet guide and confining means operatively associated with the reserve stack holding area to hold a large reserve stack of printed sheets which rests directly on the belt conveying runs close to the front of the upwardly inclined portion of said runs, said guide and confining means including rear guides toward the rear of said holding area and metering roller means at the front, said guide and confining means being adjustable laterally and longitudinally to confine printed sheets of different sizes; means for adjusting the vertical position of the metering roller means to produce shingled streams of different depths; means in the printed sheet supply hopper for sensing when the top of the small stack of printed sheets therein is between an upper level and a lower level; and means controlled by said sensing means for causing driving of the conveyor driven shaft only when the height of said small stack is between said two predetermined levels, to draw printed sheets from beneath the reserve stack and feed them in a shingled stream to the supply hopper.
 2. The apparatus of claim 1 in which the feeder frame is of an inverted L-shape, the driven shaft carrying the drive pulleys of the conveyor means is in the angle of the L, the idler pulleys are at thE front of the conveyor section, the tops of the drive pulleys and of the idler pulleys are substantially in the same horizontal plane, and the belt supporting and guiding means has a first portion that is inclined upwardly from the drive pulleys to an apex at an intermediate point close to the front of the reserve stack and a second portion that is inclined downwardly from said apex to the idler pulleys.
 3. The apparatus of claim 1 in which the belts are spaced apart, there are openings in the belt supporting and guiding means alongside the belts and beneath the reserve stack, and driven rollers with concentric high friction surfaces project through said openings to a height substantially coplanar with the top of the belt conveying runs so as to cooperate with the belts to support and feed sheets from said reserve stack.
 4. The apparatus of claim 3 in which the rollers have laterally extending integral drive drums in driven contact with the undersides of the conveyor belts.
 5. The apparatus of claim 1 in which the printed sheet guide means includes a transverse pivotal mounting to vary the angle of the reserve stack relative to the conveyor belts.
 6. The apparatus of claim 1 which includes a jogger shaft in the feeder frame drive section, an eccentric on said jogger shaft, a jogger at the front of the conveyor frame to jog the stack of printed sheets in the supply hopper, said jogger being operatively connected to the eccentric, and a driving connection between the input shaft and the jogger shaft.
 7. The apparatus of claim 6 in which jogger drive transmission means between the input shaft and the jogger shaft drives the jogger shaft continuously, and a solenoid clutch between the input shaft and the driven conveyor shaft is engaged and disengaged in response to operation of the sensing means.
 8. The apparatus of claim 1 in which the sensing means includes an actuator and an electrical limit switch, the means controlled by the sensing means includes a solenoid clutch for selectively transmitting driving force to the driven shaft, and a constantly pulsating electrical switch is wired in series with said electrical limit switch, the solenoid clutch being engaged only when both of said switches are closed, the operating of said pulsating switching imparting a jerking movement to the conveyor.
 9. The apparatus of claim 8 which includes eccentric cam means constantly driven by the drive means on the machine frame, and cam follower means for opening and closing the pulsating electrical switch.
 10. The apparatus of claim 1 in which the feeder frame is generally T-shaped, the conveyor means includes a rear conveyor section to the rear of the driven shaft which inclines upwardly to the vicinity of said shaft and then downwardly, and a front conveyor section which extends from said shaft to the front of the feeder frame, and in which the printed sheet guide means confines the reserve stack on said rear conveyor section close behind the driven shaft.
 11. The apparatus of claim 1 in which the printed sheet guide means includes inwardly extending, inclined, lateral sheet engaging members which contact the lateral margins of printed sheets in the reserve stack to partially support said stack and thereby relieve the weight on the sheets in the bottom portion of said reserve stack.
 12. The apparatus of claim 11 in which means are provided to adjust the sheet engaging members laterally to vary the amount of support that they give to the reserve stack.
 13. The apparatus of claim 12 in which the sheet engaging members are plates hinged at their upper ends; and the adjusting means comprises transverse screws engaging the lower portions of said plates.
 14. Apparatus for feeding printed sheet material to a gathering machine which has a machine frame, a printed sheet supply hopper which holds a small vertical stack of printed sheets surmounting said frame toward the front thereof, said hopper havinig a front plate, drive means on the machine frame and Means mounted in the machine frame and driven by said drive means for withdrawing sheets seriatim from the bottom of the stack at a predetermined rate and delivering them to a gathering chain which travels along the front of the machine frame, said apparatus comprising, in combination: a feeder frame of inverted L-shape which includes a short horizontal conveyor section and a structurally integral drive section which is short from front to rear depending from the rear of said conveyor section, said frame being adapted to be positioned with the conveyor section surmounting the machine frame and the drive section immediately to the rear of the machine frame; upright members on the front of the conveyor section which provide rear confining means for the sheet supply hopper and the feeder frame being bodily movable fore and aft on the machine frame to vary the length of said hopper for handling sheets of different sizes; conveyor means in the feed frame conveyor section, said conveyor means including a transverse driven shaft journalled at the rear of said conveyor section and at the top of the drive section, a plurality of drive pulleys on said driven shaft, a plurality of idler pulleys journalled at the front of the conveyor section aligned with the drive pulleys to provide pulley sets, an endless belt trained over each pulley set to form a top conveying run and a return run, and belt supporting and guiding means beneath the belt conveying runs, said belt conveying runs being inclined upwardly from the rear of the conveyor section to provide a reserve stacking holding area, and the forward portions of said conveying runs being inclined downwardly from the rear for a short distance; an input shaft journalled in the lower portion of the feeder frame drive section parallel to and substantially in the same vertical plane as the driven shaft; drive transmission means operatively connecting said input shaft to said driven shaft; means for driving said input shaft; adjustable printed sheet guide and confining means above the reserve stack holding area to hold a large reserve stack of printed sheets rests directly on the belt conveying runs close to the front of the upwardly inclined portion of said runs, said guide and confining means including rear guides toward the rear of said holding area and metering roller means at the front, said guide and confining means being adjustable laterally and longitudinally to confine printed sheets of different sizes; means for adjusting the vertical position of the metering roller means to produce shingled streams of different depths; means in the printed sheet supply hopper for sensing when the top of the small stack of printed sheets therein is between an upper level and a lower level; means controlled by said sensing means for causing driving of the conveyor driven shaft only when the height of said small stack is between said two predetermined levels, to draw printed sheets from beneath the reserve stack and feed them in a shingled stream to the supply hopper.
 15. The apparatus of claim 14 in which the tops of the drive pulleys and of the idler pulleys are substantially in the same horizontal plane, and the belt supporting and guiding means has a first portion that is inclined upwardly from the drive pulleys to an apex at an intermediate point close to the front of the reserve stack and a second portion that is inclined downwardly from said apex to the idler pulleys.
 16. The apparatus of claim 15 in which the axis of the metering roller means in a vertical plane close behind the apex of the belt supporting and guiding means.
 17. The apparatus of claim 16 in which the metering roller means is mounted for linear adjustment toward and away from the guide means.
 18. The apparatus of claim 17 in which the metering roller means is mounted for vertical adjustment to vary the depth of the shingle.
 19. The apparatus of claim 14 in whch the printed sheet guide means includes inwardLy extending lateral sheet engaging members which contact the lateral margins of printed sheets in the reserve stack to partially support said stack and thereby relieve the weight on the sheets in the bottom portion of said reserve stack.
 20. The apparatus of claim 19 in which means are provided to adjust the sheet engaging members laterally to vary the amount of support that they give to the reserve stack.
 21. The apparatus of claim 14 in which the printed sheet guide means includes a transverse pivotal mounting to vary the angle of the reserve stack relative to the conveyor belts.
 22. The apparatus of claim 14 which includes a jogger shaft in the feeder frame drive section, an eccentric on said jogger shaft, a jogger at the front of the conveyor frame to jog the stack of printed sheets in the supply hopper, said jogger being operatively connected to the eccentric, and a driving conection between the input shaft and the jogger shaft.
 23. The apparatus of claim 22 in which jogger drive transmission means between the input shaft and the jogger shaft drives the jogger shaft continuously, and a solenoid clutch between the input shaft and the driven conveyor shaft is engaged and disengaged in response to operation of the sensing means.
 24. The apparatus of claim 14 in which the belts are spaced apart, there are openings in the belt supporting and guiding means alongside the belts and beneath the reserve stack, and driven rollers with concentric high friction surfaces project through said openings to a height substantially coplanar with the top of the belt conveying runs so as to cooperate with the belts to support and feed sheets from said reserve stack.
 25. The apparatus of claim 24 in which the belts and rollers are in contact with substantially more than one-half the head to foot length of the sheets in the reserve stack.
 26. Apparatus for feeding printed sheet material to a supply box of a collating machine which has a machine frame, a printed sheet supply hopper which holds a small vertical stack of printed sheets surmounting said frame toward the front thereof, said hopper having a front plate, drive means on the machine frame, and means mounted in the machine frame and driven by said drive means for withdrawing sheets by their leading ends seriatim from the bottom of the stack at a predetermined rate and delivering them to a gathering chain which travels along the front of the machine frame, said apparatus comprising, in combination. a feeder frame which includes a horizontal conveyor section and a drive section depending from said conveyor section, said feeder frame being adapted to be positioned with the forward part of the conveyor section overlying the machine frame and the drive section immediately to the rear of the machine frame, the front of the conveyor section defining the rear of the sheet supply hopper, and the feeder frame being bodily movable fore and aft with respect to the machine frame to vary the length of said sheet supply hopper for handling sheets of different sizes; conveyor means in the feeder frame conveyor section, said conveyor means including a transverse driven shaft journalled in the conveyor section above the drive section, a plurality of laterally spaced drive pulleys on said driven shaft, a plurality of idler pulleys journalled in the conveyor section aligned with the drive pulleys to provide pulley sets, an endless belt trained over each pulley set to form a top conveying run and a return run having spaced apart belts, and belt supporting and guiding means beneath and conveying runs, there being openings in the belt supporting and guiding means alongside the belts; driven rollers with concentric high friction surfaces which project through said openings to a height substantially coplanar with the top of the belt conveying runs; an input shaft journalled in the lower portion of the feeder frame drive section parallel to the driven shaft; drive transmission means in the drive section operatively connecting said input shaft to said driven shaft; means for driving said input shaft to drive the endless belts and the rollers; printed sheet guide means operatively associated with the rear portion of the conveyor means to confine a large reserve stack of printed sheets which rests directly on the belt conveying runs and the driven rollers, said guide means being adjustable to confine printed sheets of different sizes; means in the printed sheet supply hopper for sensing when the top of the small stack of printed sheets therein is between an upper level and a lower level; means controlled by said sensing means for causing driving of the conveyor driven shaft only when the height of said small stack is between said two predetermined levels, to draw sheets from beneath the reserve stack and feed them in a shingled stream to the supply hopper; and adjustably mounted metering roller means for controlling the depth of said shingled stream as it moves from under th reserve stack.
 27. The apparatus of claim 26 in which the rollers have laterally extending integral drive drums in driven contact with the undersides of the top conveying runs. 